Gas-operated actuating system for firearms



Jan. 27, 1959 E. M. HARVEY 2,870,685

GAS-OPERATED ACTUATING SYSTEM FOR FIREARMS Filed Feb. 21, 1957 Fig -1- INVENTOR. Eu-rl: -I"1-Hu.-rv::

mozazzma 77W United States PatentO GAS-OPERATED ACTUATING SYSTEM FOR FIREARMS Earle M. Harvey, Agawam, Mass., assiguor to the United States of America as represented by the Secretary of the Army Application February 21, 1951, Serial No. 641,784

2 Claims. to]. 89-191) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention relates to actuating systems for automatic firearms and more particularly to actuating systems which are energized by gases bled from the firearm barrel.

With conventional gas systems for firearms, parts of the actuating system are mounted to the barrel along the front portion thereof and are actuated by gases bled from the barrel before the projectile leaves the bore. It is well known that gases act against the actuating parts with a terrific impact which obviously produces in the actuating mechanism vibrations which are transferred to the barrel, even though rigidly mounted to supporting means, and which cause inaccuracies in the aim of the firearm.

It is, therefore, an object of this invention to provide for firearms a gas-operated actuating system wherein none of the parts is moved until after the projectiles of the explodedcartridges have left the muzzle of the barrel.

1 It is another object of this invention to provide a gas system wherein the gases are bled from the barrel adjacent the chamber therein.

7 It is a further object of this invention to provide a gas system wherein a chambered cartridge actuates a .valve to close the gas port between the barrel and the actuating system and the pressure of the gases produced when the cartridge is fired holds such valve closed until released by a reduction in the gas pressure in the barrel when the projectile leaves the muzzle thereof.

It is a still further object of this invention to provide a gas system which is operated by the gas pressure remaining in the bore of the barrel after the exit of the projectile therefrom.

It is another and still further object of this invention to provide a gas-operated actuating system which is joined to the barrel only at the extreme breach end thereof. i

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. 1 is a side view of the gas system of this invention partially cross-sectioned to show the relationship of the parts when the barrel is empty;

Fig. 2 is a view similar to Fig. 1 but with a cartridge chambered in the barrel; and

Fig. 3 is a view similar to Figs. 1 and 2 but with the cartridge fired and the projectile still in the barrel.

' .Shown in the figures is a firearm barrel 12 having cartridge 16 and a bore 18. A cylindrical port 20 extends radially upward through barrel 12 from bore 18 and is provided at the outer end with a concentric mouth portion 22. Such mouth portion 22 is of larger diameter than port 20 and is terminated by an annular shoulder therein a chamber 14 to receive the case portion of a Patented Jan. 27, 1959 24. Mounted in barrel 12 so as to cooperate with port 20, as hereinafter described, is a valve device 26 which includes a housing 28 provided with a collar portion 30 which encircles the barrel to secure the valve device thereto and a body portion 32 which extends vertically upward from such collar portion. Provided vertically through body portion 32 is a bore 34 which has a diameter similar to mouth portion 22 and is arranged to extend axially therefrom.

With housing 28 mounted in place on barrel 12, there is inserted into bore 34 a bushing 36 having a stem portion 38 which is threadably received by port 20 and a head portion 40 which is similar in diameter to mouth 22 and is received thereby-to bottom against shoulder 24. The upper portion of head portion 40 extends upwardly from barrel 12'into bore 34 to assist. in securing valve device 26 to the barrel. Slidably received by bore 34 is a symmetrical valve member 44 having a lower rod portion 46, which is slidingly received by an axial hole 48 through bushing 36, an upper rod portion 50 of slightly smaller diameter and a cylindrical body portion 52 disposed between such lower and upper rod portions. Body portion 52 has a diameter similar to bore 34 so as to be slidable therein and is so disposed relative to lower rod portion 46 that when in contact with the top side of bushing 36, the bottom end of the lower rod portion extends into bore 18 to be engageable by the ogive of cartridge 16 so that when the cartridge is chambered, valve member 44 is cammingly moved upward. To prevent damage to the projectile when cartridge 16 is chambered, a radius is provided around the bottom end of lower rod portion 46.

.A hole 54 extends axially through valve member 44 and extending radially from such hole through body portion 52 are four passageways 56 which are arranged at right angles to each other. With valve member 44 in contact with bushing 36, the passageways 56 provide communication between an annular channel 58 provided around bore 34 and hole 54. Mounted in bore 34 above valve member 44 is a cylindrical plug 60 which is releasably secured to housing 28 by a transverse pin 62. The lower portion of plug 60 is reduced in diameter, as noted at 64, and mounted over such reduced diameter portion is a compressible spring 65 which is seated at one end against a shoulder 66 formed by reduced diameter portion 64 and at the other end against the top of body portion 52 to bias valve member 44 downwardly into contact with bushing 36. Provided in the lower portion of plug 60 is an axial well 68 having a diameter similar to that of upper rod portion 50 which is slidingly received thereby. A cylindrical cavity 70 extends downwardly from the top of plug 60 into reduced diameter portion 64 so that four equally-spaced ports 72 extending radially into such reduced diameter portion provide communication between the chamber formed by such reduced diameter portion and the walls of bore 34 and cavity 70.

A gas cylinder 74 is mounted to housing 28 to extend rearwardly therefrom in axial alignment with the annular channel 56 and an aperture 76 provides communication between such channel and gas cylinder. Whereby, when valve member 44 is in normal position, there is communication between bore 18 and gas cylinder'74, permitting gases from such bore to enter the gas cylinder and actuate a piston 78 mounted therein. The diameters of the passageways 56 and the width of channel 58 are such that when the bottom end of valve member 44 rests on the cylindrical portion of the projectile of cartridge 16, such passageways and channel are out of communication so that gases from bore 7$ are pre 'vented from entering gas cylinder 74.

Operation Thus, when a cartridge 16 is moved into chamber 14 of barrel 12, the ogive of the cartridge earns the bottom end of valve member 44 upwardly onto the cylindrical' portion of the projectile against the bias of spring 65 With valve member 44 in raised position, gases are prevented from entering gas cylinder 74, as hereinbefore described. When cartridge 16 is fired and the projectile is propelled forwardly along bore 18, valve member 44 remains in raised position by the pressure of the propelling gases because of the difference in the areas of the top end of upper rod member 50 and the larger bottom end of lower rod portion 46.

The relationship between thedifierence in the forces exerted against the oppositeendssof valve memher44 and the force exerted by spring 65 against such valve member is such that immediately after the cartridge projectile has left the muzzle of the barrel 12, the resulting drop in gas pressure in'bore 18 permits the spring to immediately overcome the gas pressure remaining in bore 18 and moves valve member 44 downwardly while such gas pressure is sufiicient to operate piston 78 when passageway 56 aligns with aperture 76. Port 72 and cavity 70 are provided to bleed to the atmosphere any gases which seep past valvemember 44 and might affect the forces applied against such valve member.

From the foregoing it is clearly apparent that there is herein provided for firearms a gas-operated actuating system wherein none of the parts is moved until after the projectiles of the exploded cartridges have left the muzzle barrel so as not to disturb the accuracy of the firearm, with the system being simple and rugged in construction and easy to manufacture.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

I claim:

1. In a firearm having a barrel with a chamber for receiving a cartridge with a projectile and a bore for the passage of the projectile after the cartridge is fired and a gas cylinder with a cooperating piston, an actuating system including a passageway communicating between the bore and the, gas cylinder, a valve engageable with the projectile when the cartridge is chambered for blocking said passage and subjectable to the gas pressure in the bore after they cartridge is fired and while the projectile is in flight in the bore for holdingv 2. In a firearm having a barrel with a chamber forr'e'ceiving'a cartridge with a'projectile an'd a-bore for the passage of the projectile when the cartridge is fired and a gas cylinder with a cooperating piston, an'actuating' system including a passageway extending from the bore adjacent the chamber to the gas cylinder, a valve member engageable by the projectile of the cartridge when chambered for movement into position to releasably block' said passageway, a spring for biasing said valve member into position for unblocking said passageway, opposing end' portions on said valve member of different areas subject to the pressure of the gases in the bore for holding said valve member in said blocking position while the projectile is inflight in the bore, and

said difierences. of areas and the bias of said spring being so related that said, spring moves said valve member to unblock said passageway after the projectile leavesthe bore, and while there is sufficient pressure, in the bore to operate the, piston.

References Cited, in the file of this patent UNITED .STATES PATENTS 1,020,596 Brauning Mar. 19, 1912 2,149,512 Eiane Mar. 7, 1939, 2,482,880

Sefricd Sept. 27, 19,49 

